Chemical Forums

Specialty Chemistry Forums => Citizen Chemist => Topic started by: BROe on December 09, 2018, 04:50:01 PM

Title: Large terbium sulfate crystals
Post by: BROe on December 09, 2018, 04:50:01 PM

I am going to attempt to make some Terbium(III)Sulfate for its fluorescent properties. Synthesis videos (https://www.youtube.com/watch?v=DJcObFauFIc) I have seen show that the salt is not very soluble in water. I have also read (http://sciencemadness.wikia.com/wiki/Terbium_sulfate) that its solubility decreases in hot water, but it tends to supersaturate. These things make it seem like obtaining crystals on anything larger than a millimeter scale would be very difficult.

Does anyone have any suggestions on how I could go about trying to grow centimeter-scale crystals? The only thing I can think of is to use enough water to dissolve everything and let it evaporate slowly over a period of weeks, but maybe someone else knows a better way.

Thanks

Title: Re: Large terbium sulfate crystals
Post by: jeffmoonchop on December 10, 2018, 01:51:38 PM

are there any solvents which solubilise it more? In any case, if you can hold at elevated temps, you can choose the largest crystal, tie it with a thread and suspend it in the supersaturated solution. Even if there are smaller crystals still in the bottom, the larger suspended crystal will still grow. Look up Ostwalds ripening. But it is better when the solution is free from other crystals so filtering the solution into a clean container every so often will help with the growth.